In the vicinity of Mont Blanc. 189 



as to reduce to symmetrical order a large tract of the Secondary 

 rocks north of and around Salzburg, and to exhibit in regular order 

 the succession of the Secondary and Tertiary rocks in their eastern- 

 most extremity, where the Alps die away into the plains of Styria.' 



From such efforts, and particularly from the excellent researches 

 of Leopold von Buch, Boue, Studer, and others which followed, the 

 true order was gradually extended to the more complicated region 

 of the west, in several parts of which, wliere complicated crystal- 

 line rocks — whether igneous or metamorphic — most aboimd, other 

 distinguished German geologists besides von Buch had been for 

 many years occupied. 



Among the French geologists, no one had more distinguished 

 himself tham M. Elie de Beaumont in elaborating the effects of the 

 great intrusions of granitic and other igneous rocks in the Western 

 Alps, and in explaining the abnormal position into which the 

 original deposits had been thrown. In the same way von Buch, 

 who wandered during many a year, on foot, through all the recesses 

 of the Alps, has, in his maps and writings left behind him frequent 

 proofs of the effects produced by granites and porphyries upon the 

 sedimentary deposits which they have invaded.'^ 



But to no school of geologists who have been working out the 

 original symmetry of the Eastern Alps have we been more indebted 

 of late years than to the Austrians, who have succeeded in assigning 

 to some of the great central calcareous masses of the chain their 

 places in the geological series much more exactly than was pre- 

 viously known, and to delineate them in detailed and well finished 

 maps, published under the direction of the Imperial Eoyal Geological 

 Institute, presided over by its veteran leader, Haidinger.^ The 

 clear proofs of the existence of the Trias, and its calcareous centre, 

 the Muschelkalk, though long ago indicated by von Buch, is one 

 of the great recent trophies of those Austrian geologists. 



But passing from tliis rapid glance at the methods by which a 

 general acquaintance with the structure of the whole chain has been 

 attained, we return to the consideration of the mountains and valleys 

 around Mont Blanc. It is this region, so broken and so complicated, 

 and which seemed to baffle the industry of that accurate mineralogical 

 geologist, Necker de Saussure, which M. Alphonse Favre has described ; 

 and his task, we are bound to say, has been accomplished in a masterly 



1 The Geological Map of the Eastern Alps (Trans. Geol. Soc. 2nd Series, vol. iii- 

 p. 35) which comprised the result of these and other researches, was executed by 

 Murchison after the labour of three summers. It exhibited the real order of succes- 

 sion then known (1831), from the axial and oldest rocks to the secondary and tertiary 

 deposits on either flank of the chain. See 2nd ser., vol. iii., pi. 35, in the Trans. Geol. 

 Soc, with description thereof. See Sedgwick's explanatory preamble. 



* See particularly the Maps of the Alps published by Martin Schropp & Co., Berlin? 

 which are essentially the results of the labours of von Buch. 



3 To obtain a just appreciation of the value of the labours of the Austrian 

 geologists, it is only necessary to inspect the sheet (No 5) of the remarkable general 

 Map of the Austrian Monarchy, by Herr k. k. Director, Dr. Franz Bitter von Hauer, 

 in which the various rocks of the Tyrolese, Milanese, and Venetian Alps are defined 

 by 48 distinct colours and signs. 



